How does sleep affect weight?

Many studies have now shown that an acute deprivation of sleep is associated with decreased leptin levels and increased ghrelin levels. These effects have been seen independently of age, sex and BMI. To understand how this works, we first of all need to know a little bit about leptin and ghrelin.

What is leptin?

Leptin is a protein produced by adipocytes (fat cells). The amount secreted is based on the mass of adipose tissue (fat) an individual has – more is released in individuals who are overweight/ obese than those who are lean and therefore have less adipose tissue.

Leptin plays an important role in the regulation of energy balance. It sends messages to the brain that signal for the cessation of food intake and the regulation of body weight/ stimulation of metabolic rate. It is classed as an anorexigenic factor, which is a hormone, compound or drug that works as an appetite suppressor.

The leptin feedback mechanism

It has however been postulated that obese individuals have leptin resistance, allowing them to eat more despite the appetite inhibiting effects of leptin. Leptin resistance could be due to an increase in C-reactive protein (CRP) – a protein that is increased with obesity and also sleep loss [1]. Leptin binds to circulating CRP and this can lead to decreased effectiveness of leptin [1].

What is ghrelin?

Ghrelin is produced by the stomach and signals for hunger. It is known as an orexigenic hormone – orexigenic compounds, hormones or drugs work to stimulate appetite. Levels of ghrelin are lower in obese individuals and higher in lean individuals. Once you have eaten, ghrelin levels are reduced.

Factors influencing the release of ghrelin:

Regulators of circulating ghrelin

Effect on circulating ghrelin

Food intake

Decreases

Age

Decreases with increasing age

Gender

Increased levels in females over males

BMI

Decreases with increasing BMI

Glucose

Decreases

The above table was adapted from Klok M et Al. [2]

What is the role of sleep in weight management

Putting it all together…

Increased appetite

The levels of circulating leptin are depressed in sleep deprived individuals. This results in a lesser amount of control over the regulation/ suppression of appetite. This means that we can eat more than normal before our body tells us we have had enough.

To confound matters, an increase in ghrelin levels is also associated with sleep deprivation. This increases appetite and consequently the amount of food we desire. These two things together therefore influence the quantity of food we want to eat which is generally more than we would normally eat if we had received a good night sleep. There has even been a direct association between short sleep duration and an increased BMI [3].

Altered eating habits

An increase in irregular eating habits is also seen with reduced sleep duration. For instance, increased snacking between meals reduced vegetable intake and food choices that are more energy dense. This can be tied to the physiological changes of ghrelin and leptin secretion and also the emotional side effects experienced with sleep deprivation e.g. the tendency to want comfort foods or feeling as though more food is needed to provide additional energy to get through the day.

Decreased physical activity

Another potential reason for weight gain is that we are generally less inclined to be as active if we are feeling fatigued. So with sleep deprivation, appetite is increased yet physical activity is decreased. This can easily throw off the energy input vs. output balance.

The diagram below sums up these potential causes for weight gain due to lacking sleep.

The above diagram was taken from The Metabolic Consequences of Sleep Deprivation [1].

× NEAT stands for Non-exercise activity thermogenesis which is the energy we expend for everything bar sleep, sport or eating. Examples include walking, household chores, typing and fidgeting – these are incidental activities that can increase metabolic rate.

Getting the best night sleep you can, could therefore assist in weight loss and weight management – it will help with control over the amount we eat and making healthier choices.

Tips for improved sleeping habits

√ Have a routine that your body can adapt to. Having a mix of late nights and late mornings will throw your body clock out and make it more difficult to get sleep.

√ Avoid using electronic devices immediately before bed e.g. watching TV or playing video games. It can take longer for your brain to switch off.

√ Turn off your mobile phone or set it to the ‘do not disturb mode’.

√ Make sure you don’t go to bed extremely hungry or too full. You may be too focused on these issues to fall asleep.

√ Try not to drink too much fluid just before bed so you aren’t disturbed by needing to get up throughout the night.

√ Make sure you are comfortable e.g. ensure the room is dark enough and quiet enough.

For more advice on weight management, see my blog on ‘Healthy Weight Loss’.

Contact us for results focused advice about eating healthy

For more information about weight management, make an appointment with our dietitian Belinda Elwin. ENT Wellbeing can be reached on 1300 123 368 and are happy to help with any diet related issues or questions.

References

2. Klok M, Jakobsdottir S, Drent M. Appetite Regulatory Peptides: The role of leptin and ghrelin in the regulation of food intake and body weight in humans: a review. Department of Endocrinology, VU University Medical Center. Revised 9th March 2006.

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About Belinda Elwin

Belinda is a fully Accredited Practicing Dietitian and Nutritionist who has experience working with both children and adults. She is constantly ensuring her knowledge is up to date by attending conferences, workshops and keeping on top of newly emerging evidence.

Belinda has worked within the community by conducting supermarket tours and regularly delivering presentations to schools and support groups. Additionally, she leads a healthy lifestyle program for children outside of the healthy weight range. During the week, she also works with inpatients in the public hospital system.

Belinda combines her experience and skill set to provide practical, client specific advice through dietary counselling. In particular, Belinda has a broad range of experience with weight management, diabetes, oncology, high cholesterol, malnutrition, childhood nutrition and gastrointestinal disorders. She is passionate about her career and helping others to improve their quality of life.

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We are Dietitians and Nutritionists, Speech Pathologists and Skincare Specialists. We see adults and children from our office in Randwick. Passionate about health and wellbeing, we write about issues relevant to our clinical practice.